Laboratory of Plant Phylogenetics and Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, P. R. China.
Am J Bot. 2011 Sep;98(9):1520-36. doi: 10.3732/ajb.1100006. Epub 2011 Aug 22.
The Persea group (Lauraceae) has a tropical and subtropical amphi-pacific disjunct distribution with most of its members, and it includes two Macaronesian species. The relationships within the group are still controversial, and its intercontinental disjunction has not been investigated with extensive sampling and precise time dating. •
ITS and LEAFY intron II sequences of 78 Persea group species and nine other Lauraceae species were analyzed with maximum parsimony and Bayesian inference. Divergence time estimation employed Bayesian Markov chain Monte Carlo method under a relaxed clock. •
Several traditional genera or subgenera within the Persea group form well-supported monophyletic groups except Alseodaphne and Dehaasia. The divergence time of the Persea group is estimated as ∼55.3 (95% higher posterior densities [HPD] 41.4-69.9) million years ago (mya). Two major divergences within the Persea group are estimated as ∼51.9 (95% HPD 38.9-63.9) mya and ∼48.5 (95% HPD 35.9-59.9) mya. •
Persea can be retained as a genus by the inclusion of Apollonias barbujana and exclusion a few species that do not fit into the established subgenera. A major revision is recommended for the delimitation between Alseodaphne, Dehaasia, and Nothaphoebe. We suggest that the Persea group originated from the Perseeae-Laureae radiation in early Eocene Laurasia. Its amphi-pacific disjunction results from the disruption of boreotropical flora by climatic cooling during the mid- to late Eocene. The American-Macaronesian disjunction may be explained by the long-distance dispersal.
榆科（Lauraceae）的 Persea 属（榆科）具有热带和亚热带的环太平洋间断分布，其大部分成员都属于该属，并且包括两个马卡龙西亚物种。该属内的关系仍然存在争议，并且其洲际间断尚未通过广泛采样和精确的时间测定进行研究。
采用最大简约法和贝叶斯推断法分析了 78 种 Persea 属物种和其他 9 种樟科物种的 ITS 和 LEAFY 内含子 II 序列。贝叶斯马尔可夫链蒙特卡罗法在松弛时钟下进行了分歧时间估计。
除 Alseodaphne 和 Dehaasia 外，Persea 属内的几个传统属或亚属形成了支持良好的单系群。Persea 属的分歧时间估计为约 5530 万年（95%高 posterior densities [HPD] 4140-6990 万年）前。Persea 属内的两个主要分歧估计为约 5190 万年（95% HPD 3890-6390 万年）前和约 4850 万年（95% HPD 3590-5990 万年）前。
通过包含 Apollonias barbujana 和排除不符合已建立亚属的几个物种，可以将 Persea 保留为一个属。建议对 Alseodaphne、Dehaasia 和 Nothaphoebe 之间的界限进行重大修订。我们建议，Persea 属起源于早始新世劳亚古陆的 Perseeae-Laureae 辐射。其环太平洋间断是由中晚始新世气候变冷导致热带植物区系破坏造成的。美洲-马卡龙西亚间断可能是由远距离扩散解释的。
